Collet



j articles.

atented Uct. 25, 1927.

.Nrrso STAT-Es 'ERNEST E. MINARD, OF DETROIT, MICHIGAN.

COLLET.

Application led February 23, 1926. l Serial No. 89,919.

ln my pending application Serial No. 22,794, filedApril 13. 1925, there is disclosed a feed collet used in automatic and hand operated screw machines, bar forming machines and the like for feeding stock so that an end portion of the stock may be operated upon for the production of screws and other The feed collet is adapted to in termittently advance stock and a well known type of collet includes resilientl fingers formed from a tubular piece of material. The resilient fingers disclosed in my pending application are provided with interchangeable pads or grpping jaws having lugs exr tending outwardly into thefingers, and this invention aims to provide somewhat of a reverse arrangement, that is providing the fingers with inwardly projecting lugs or the equipment thereof adapted to engage in the` pads or gripping jaws. I have found that time and labor may be saved by providing the resilient, lingers with pad retaining means, consequently a cheaper article of manufacture is produced that has all, if not more, advantage of the lug equipped pads disclosed in my pending application.

My invention will be hereinafter described and then claimed, and reference will now be had to the drawing, wherein Figure 1 is a longitudinal sectional view of a form of collet having pads held 'by .finger lugs, the fingers and pads being illustrated as though holding a piece of stock shown by dot and dash lines;

' Fig. 2 is a cross sectional view taken on the line II--H of Fig. 1;

Fig. 3 is aside elevation, partly broken away and partly in section, of. 'a collet having pads held somewhat similar to the pads shown in Figs. 1 and 2;

v Fig. 4 is a cross sectional view taken on the line IV--IV of Fig. 3;

Fig. 5 is 'a longitudinal sectional view of a portion'of another form'of collet, showing the pads as though separated by a piece of Fig. 6 is a. cross sectional View taken onA the line VI-VI of Fig. 5;

Fig. 7 is a plan of a portion of the collet shown in Figs. 5. and 6;

Fig. 8l is a longitudinal sectional view ot` a portion of still another form of collet showing the pads as though separated by a piece of stock; f

Fig. 9' is a plan of the same; y

Fig. 13 is an elevation of a tool that may be advantageously-i used in the removal of pads from a collet.

Reference will first be had to Figs. 1 to.

4 inclusive, and Fig.'12 wherein 1 denotes a collet adapted to be placed'in a machine and reciprocated therein to intermittently feed `a piece of stock 23 extending through the collet. For this purpose the colletis formed from a cylindrical body or tube which is longitudinally slitted, as at 2 to provide opposed resilient semi-cylindrical fingers 3. Mounted in the outer end ofthe collet are opposed semi-cylindrical pads 4 having inner beveled ends 5 to permit of the forward `end of the piece of stock 23 easily encountering said pads, and the outer ends of the pads and the fingers 3 have beveled edges 6 to afford clearance and permit of the pads contacting, as shown in Fig. 12. This contacting of the pads, at a point intermediate the' ends thereof, will prevent the pads from tilting relative toeach other and will main-Y tain a snug engagement of the pad walls with the finger walls so that burrs or other matter cannot enter or wedge between the inner ends of the pads and the fingers, which in time might cause displacement of the pads. To hold the pads 4 in place against longitudinaldisplacement by a piece of stock,.

said pads have transverse slots 7 and 4extending into said slots are inwardly struck lugs 8 of the fingers 3. The lugs 8'l are formed by providing the fingers 3, adjacent the outer ends thereof, with parallel transverse slits 9 and the material between said slits is .struck inwardly to form the ,transverse lugs 8 which have abrupt side shoulders 10 dis- 'posed at approximately a right angle to the longitudinalaxis of the collet. As shown in Fig. 2 the abrupt shoulders 10 are adapted to engage similar shoulders or side walls of the pad slots 7 and in order that the lugs 8 will snugly fit l,inthe pads an'd not interfere with the movement of'stoclr between Athe pads, the lugs have central arcuated portions 11v so that the inner walls of said lili lugs will cooperate with the inner walls of' the pads 4 in providing a cylindrical end passage for the collet. In other words, the

linner walls of the lugs 8'are flush with the inner walls of the pads, as best shown in Fig. 2, and the arcuated portionsl 11 of said lugs afford a better distribution of the metal to prevent displacement of the side walls of the collet fingers. In some instances, as

shown in Fi". 1l the luefs 8 ma not comf plctely fill the slot 7 of` the pads 4, but may lspan the joint between the pads and fingers,

thusI givingv the lugs a firmer position, so

that a pad, under endwise pressure on a pie-ce of stock, cannot sever a lug from its finger. Obviously the side shoulders 1() of( .the lugs are braced throughout their length,

in addition to the end connections with the fingers.

Instead of providing the lugs 8 with arcuated portions, said lugs may be straight, as shown in Figs. 3 and 4 in which instance the slots 12 in t-he pads 13 are of less depth than the slots 7 in the pads 4, consequently the side area of the finger lugs shown in Fig. 4, will which may be spot welded to the inner walls of the fingers 3 and extend into openings 15 provided therefor in pads 16. Instead of making the lugs 14 independent of the collet fingers 3 and then connecting the lugs to said fingers I may punch or otherwise operate upon the collet vfingers 3 to provide instruck lugs 17, as shown in Figs. 8, 9, and 10. The lugs 14 and 1 7 are preferably cylinderical and are simply instances of other forms of lugs than those disclosed 'in Figs. 1 to 4 inclusive. In all forms the lugs prevent accidental displacement of the pads, yet permit .of the pads moving inwardly towards each other and removal ofV said pads from the fingers. 4

In Fig. 13 I show a,4 tool that may be advantageously used for removing the pads when necessary. This tool comprises a U-shaped resilient holder 18 provided with heads 19l having wedge members 20 and wedge members 21, the wedge members 2O 'being morel acute than the wedge members 21.

lI show the small wedge members as entering the shts 2 of the collet to force the collet `fingers apart and for this purpose the tool the uppermost pad may be shifted outwardly y from the end of a collet.- The lowermost pad can then be raised and easily removed from the end of the colet. This ready removal of the collet pads isa feature of my invention which facilitates operations and production in connection with a screw machine, and the fact that the pads are positively held against longitudinal displacement and against turning or tilting movement relative to the Acollet fingers prevents, to a large degree, the accumulation of anyburrs. chips or the like between the pads and the collet fingers and obviates any particular attention or care of thepads until the same may be worn and need replacing.

vFrom the foregoing it will be observed.

that" I haveillustrated the collet as though the fingers were stressed and a piece of stock extending therethrough. vIt will also be noted, that the molinting and demounting of the pads involves a method of procedure and for this reason I do not care to confine my invention to any details of construction, for carrying out the method, other than defined 'in the appended claims.l

IVhat I claim is:

1. A feed collet comprising fingers, pads, a connection between said fingers and pads, said connection being formed by portions having a configuration which prevents longitudinal and turning movement of said pads relative to said` fingers and permits radial shifting of said pads towards each other at opposite sides of the axis of said collet without said pads becoming disconnected from said fingers.

2. A feed collet made of tubular material that may be struck outwardly, said collet comprising interengaging fingers and pads, the engagement between said vfingers and pads being in the form of contacting shoulders withsome of said shoulders outstruck from said fingers. l

3. A feed collet made of tubular material that may be struck inwardly, said collet comprising fingers, pads against the inner walls of saidv fingers and free to move inwardly towards each other, and means struck inwardly from said lingers to engage in said pads and prevent vlongitudinal or turning movement of saidj pads relative to said fingers.

4. A collet comprising spaced apart fingers, pads against the inner `walls of said' fingers, means carried by said fingers and extending into said pads to prevent longitudinal movement of said pads relative to said fingers, said means spanning a joint between said pads and fingers so that there is a constant interengagement ofsaid fingers and pads.

In testimony whereof I affix my signature.

animera. MINARD, 

